Annular seals for pistons, gas cylinders, or other applications where surfaces slide against each other often suffer from numerous issues. Current seals lack sufficient structural support to resist flexing, which can cause the seal to wear out quickly especially in high temperature applications (e.g., greater than 350 degrees Celsius). In addition the sealing surface of current seals can cause excessive wear against an adjacent sliding member due to an overly broad contact area.
What has yet to be appreciated is an annular seal can be constructed to have high structural support while also limiting the contact of a sliding sealing surface (e.g., an outer cylindrical surface of the seal). For example, seals can be constructed where a rib is disposed on the outer wall of the seal. The rib provides a sealing surface having a reduced contact area and the rib-wall assembly forms a beam structure providing greater structural integrity to the annular seal.
Annular seals have been discussed in the past. U.S. Pat. No. 4,770,093 to Adamek and U.S. Pat. No. 4,709,933 to Adamek et al., both discuss fire resistant seals. However, the contemplated seals are stationary and are not adapted to provide a rib having sliding sealing surface. U.S. Pat. No. 5,872,323 to Norton et al. describes a ring-shaped piston seal for use in a firearm that lacks a rib structure. International patent application WO 2006/015324 to Liepold et al. discloses a sealing joint between two mutually moveable members using deformable ribs that insert into channels. However, the Liepold approach cannot be used in translating applications where a seal must slide or translate against an adjacent member. The above and other existing seals represent contemplated designs that lack the ability to scale from small applications having scales measured in tenths of an inch (e.g., small piston engines) to large applications having scales of approximately 10 feet (e.g., industrial gas turbine engines).
These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Thus, there is still a need for annular seal that scales from small applications to larger applications.